1. Field of Invention
This invention relates to watercraft, and more particularly to a frame, an inflatable skin, and a watercraft formed from same and methods of assembly.
2. Description of Related Art
Inflatable watercraft have become tremendously popular as practical and efficient outdoor gear. Inflatable watercraft have allowed outdoor adventurers to access relatively remote locations due to their ability to be disassembled and quickly reassembled. Inflatable watercraft also respond actively to changing water conditions by absorbing wave energy such as from ocean surges for example, giving paddlers a sense of security. In addition, inflatable watercraft have also provided an inexpensive mode of aquatic enjoyment for use by both novice and seasoned paddlers in whitewater rapids, flat lakes, mild rivers, or ocean, for both day trips and extended wilderness expeditions. Inflatable watercraft are popular in whitewater rapids for example because they are wide and very stable, which allows beginners to tackle rapids they would be unlikely to attempt in a hard shell boat.
However, inflatable watercraft have typically been used mostly for whitewater alone because they are more sluggish than hard shell boats on flatwater, due to a tendency to sag amidships when loaded with gear or passengers, causing lifting of the bow and stern of the watercraft. While a degree of bow and stern lift allows the watercraft to more easily pivot and reduces the entry of water into the bow and stern of the watercraft, too much lift can cause the watercraft to be more adversely affected by large waves, increasing the risk of swamping from transverse waves especially. In addition, a wind blowing upstream can cause a lifted bow or stern of an inflatable watercraft to act like a sail, making. even downstream progress more difficult.
Inflatable watercraft used on flatwater usually have problems tracking (holding a straight-line course without constant paddle correction) since most inflatable watercraft lack a keel bar and thus have a significant component of drift, especially over long distances.
Attempts to overcome these problems have involved employing an isoskeleton frame comprising a plurality of longitudinal and transverse supports forming plaquettes inside an outer skin of a watercraft to provide enhanced rigidity. Inflatable air bladders have been employed in only a few of the plaquettes of the isoskeleton frame to provide flotation of the watercraft. The inflatable air bladders by themselves do not form a hull shape and cannot support the weight of passengers or gear nor do they provide a watertight surface. Further there are many parts to the isoskeleton frame, which can be lost and/or damaged, and such an arrangement does not provide the same floatation and durability to impacts with rocks for example that strictly inflatable watercraft without frames can provide.
What is desired therefore is a watercraft that overcomes these problems.
The present invention addresses the above needs by providing a frame for a watercraft, an inflatable skin for a watercraft, and a watercraft formed from same.
In accordance with one aspect of the invention, there is provided a watercraft comprising an inflatable skin operable to define a hull shape when inflated and a frame comprising an extendible rigid keel member engageable with the inflatable skin to stretch the inflatable skin to define a rigid keel form in the inflatable skin.
The extended rigid keel member provides for a fairly straight hull to reduce sag of the watercraft when loaded with gear or passengers. This gives a longer waterline compared to the overall length of the watercraft than an inflatable watercraft without a frame support, and allows the watercraft greater maneuverability and less susceptibility to deleterious effects of strong winds and large waves. In addition, the presence of the defined keel form provides greater tracking ability than an inflatable watercraft without a frame. The defined keel form also gives a bow of the inflatable watercraft a defined shape which reduces turbulence and increases speed.
In accordance with another aspect of the invention, there is provided an inflatable skin for a watercraft. The inflatable skin includes a port hull portion and a starboard hull portion, the port and starboard hull portion being operable to receive an extendible rigid member of a frame lengthwise therebetween, and bow and stern connectors operable to connect the inflatable skin to the frame near a bow and a stern of the watercraft, respectively. The inflatable skin is operable to define a hull shape when inflated, and is engageable with the frame to stretch the inflatable skin to define a rigid keel form in the inflatable skin.
The port and starboard hull portions may be inflatable and may be connectable together to form a keel pocket to accept the keel member. The keel member may be receivable lengthwise between the port hull portion and the starboard hull portion.
The port and starboard hull portions may include port and starboard chambers operable to receive respective inflatable sponsons. The inflatable skin may also include inflatable sponsons operable to be received in the port and starboard chambers. Alternatively or in addition, the port and starboard chambers may be airtight and operable to be inflated.
The port and starboard hull portions may have closeable openings to provide access to the port and starboard chambers to permit insertion and removal of the respective inflatable sponsons.
The port and starboard hull portions may include port and starboard hull and deck chambers, respectively. The port and starboard deck chambers may be operable to receive port and starboard deck sponsons, and the port and starboard hull chambers may be operable to receive port and starboard hull sponsons, respectively, and may have closeable openings for receiving the port and starboard deck and hull sponsons, respectively. The port and starboard deck and hull inflatable sponsons may also be included. The inflatable skin may further include port and starboard dividers dividing the port and starboard chambers into port and starboard deck and hull chambers.
The inflatable skin may also include a hull skin portion and port and starboard deck skin portions. The hull skin portion and port and starboard deck skin potions may be comprised of an abrasion resistant, waterproof fabric, such as urethane, neoprene, polyvinyl chloride, or rubber coated nylon or polyester fabric. The hull skin portion may be operable to support a skeg.
A seat may be connected to the port and starboard deck skin portions, to facilitate seating of a user.
In accordance with another aspect of the invention, there is provided a frame for a watercraft. The frame includes an extendible rigid keel member engageable with an inflatable skin of the watercraft to stretch the inflatable skin to define a rigid keel form in the inflatable skin.
The keel member may include first and second keel member portion pivotally connectable to each other, and a lock operable to lock the first and second keel member portion against relative pivotal movement.
The frame may also include port and starboard chine stiffeners connectable to the keel member to extend lengthwise along port and starboard sides of the inflatable skin, and may extend lengthwise between a port deck chamber and a port hull chamber, and lengthwise between a starboard deck chamber and a starboard hull chamber, respectively, of the inflatable skin. The port and starboard chine stiffeners, and the keel member may be pivotally connectable to each other.
The frame may also include a bow joiner and a stern joiner to connect the keel member, and the port and starboard chine stiffeners together, respectively. The bow and stern joiners may cooperate with bow and stern connectors on the inflatable skin to connect the inflatable skin to the frame at a bow and a stern of the watercraft, respectively. The keel member, port and starboard chine stiffeners may be shaped to curve upwardly for receipt into a receptacle on the inflatable skin to lie on port and starboard deck chambers of the inflatable skin, respectively.
The port and starboard chine stiffeners may be collapsible, and the keel member and the port and starboard chine stiffeners may include a plurality of detachable stiffener portions. Further, at least one of the port and starboard chine stiffeners may include a foot support.
The frame may also include port and starboard gunwale stiffeners connectable to the keel member to extend lengthwise over port and starboard sides of the inflatable skin, and may extend lengthwise over a port deck chamber, and lengthwise over a starboard deck chamber, respectively, of the inflatable skin.
The port and starboard gunwale stiffeners, and the keel member may be pivotally connectable to each other, and the port and starboard gunwale stiffeners may be collapsible. The keel member and the port and starboard gunwale stiffeners may comprise a plurality of detachable stiffener portions.
The keel member of the frame may be operable to support a skeg, and the frame may include the skeg.
In accordance with another aspect of the invention, there is provided a method of assembling a watercraft. The method includes engaging an elongated keel member of a frame with an inflatable skin operable to define a hull shape when inflated to stretch the inflatable skin to define a rigid keel form in the inflatable skin. The elongated keel member of the frame may be engaged with the inflatable skin by pivoting a first portion of the keel member relative to a second portion of the keel member, and also may include locking the keel member portions against relative pivotal movement when the keel member is engaged with the inflatable skin. The method may also include engaging a chine stiffener with the inflatable skin to stiffen the inflatable skin. This may include rotating the chine stiffener downwardly towards the keel member to stretch the inflatable skin longitudinally along the keel member. The method may also include inflating the inflatable skin.
The keel member of the frame when extended defines the rigid keel form, which curves upward at the bow and stern of the watercraft. The chine and gunwale stiffeners of the frame when expanded resist the upward curvature of the bow and stern, leading to a longer waterline and a faster watercraft.
The features of the frame, inflatable skin and the watercraft formed from same provide a relatively inexpensive, light weight watercraft which can be quickly assembled and disassembled for economy of storage and ease of transport to distant aquatic locations. The materials used for the watercraft allow for low-cost repairs and ease of replacement of parts. Further the watercraft described herein provides rigidity against sag, maneuverability, and ease of movement in various water conditions, thereby providing performance comparable to that of hard-shelled watercraft.
Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction wit the accompanying figures.